Transradial Intervention via Large-Bore Guide Catheters: A Study of Coronary Bifurcation Disease Treatment Using the Crush Technique

Abstract: Transradial access for coronary intervention significantly reduces vascular complications and may be associated with a reduced risk of major adverse cardiovascular events. However, the small caliber of the radial artery has been considered a limitation to performing complex coronary intervention. Fifty-three patients with true bifurcation disease, in whom a two-stent strategy was felt to be indicated, were scheduled to undergo crush stenting via the transradial approach. Procedural outcome was recorded and 6- and 18-month clinical follow-up was performed. Successful crush stenting via the radial artery was performed in 51/55 lesions (93%). Crush stenting was performed in 53 lesions overall and successful final kissing inflation was achieved in 51/53 (96%). There were no in-hospital or procedural complications. The overall rate of death, myocardial infarction, or target vessel revascularization was 9.8% at 18-month follow-up. Complex percutaneous coronary intervention requiring large-bore catheters can be performed successfully in a high proportion of patients via the transradial approach. Crush stenting, with a very high rate of final kissing inflation, was associated in this series with excellent procedural and medium-term outcomes.

J INVASIVE CARDIOL 2013;25(9):455-459

Key words: percutaneous coronary intervention, stent, coronary bifurcation, radial, transradial, crush technique

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Transradial access for coronary intervention significantly reduces vascular complications, is preferred by patients to the femoral approach, and may be associated with a reduced risk of major adverse cardiovascular events.^1,2 Despite its advantages, the small caliber of the radial artery has been considered a major limitation to performing complex percutaneous coronary intervention (PCI) requiring large-bore (>6 Fr) guide catheters. However, many radial arteries will accept a 7 Fr sheath³ and the introduction of newer technologies such as sheathless catheters, which have a substantially smaller outer diameter than conventional guide catheters, may allow these complex cases to be performed routinely via transradial approach.^4-6

Bifurcation disease is common and the optimal treatment remains controversial. Although one-stent strategies are generally recommended for most bifurcation disease,^7,8 a two-stent strategy may still be preferable when the side branch is large caliber and/or supplies a significant area of myocardium.⁹ Crush stenting is a two-stent strategy that ensures the patency of both branches at all times during the procedure and requires a minimum 7 Fr guide.

The primary aim of this study was to investigate the feasibility of performing a complex technique necessitating the use of large-bore guide catheters (crush stenting, minimum 7 Fr internal diameter) via the transradial approach. As a secondary aim, the angiographic and clinical results of crush stenting were analyzed in this cohort of patients.

Methods

Between March 2005 and April 2008, patients with true bifurcation disease (Medina classification 1,1,1 or 0,1,1) and a side-branch diameter of at least 2.5 mm by visual estimation, and in which a two-stent strategy was felt to be indicated, were scheduled to undergo crush stenting performed by the transradial approach as the default strategy. Procedures were performed by one of three high-volume radial operators (DGF, FFO, JE). 

Procedural technique. Arterial access was obtained via the right radial artery or, if unsuccessful, via the left radial artery. All patients received dual-antiplatelet therapy with aspirin and clopidogrel, anticoagulation with intraarterial heparin and intraarterial glyceryl trinitrate. Preprocedural radial ultrasound was not performed. In the majority of cases, a 7 Fr arterial sheath and conventional 7 Fr guide catheter were used. However, toward the end of the series, 7.5 Fr sheathless guiding catheters (Eaucath; Asahi Intecc) became available for use at our center. If radial access was unsuccessful, then the procedure was performed via femoral access.

Crush stenting was performed as described by Colombo and colleagues.¹⁰ Following lesion preparation, the main and side-branch stents were positioned with the main-branch stent covering the proximal extent of the side-branch stent. The side-branch stent was deployed first. The side-branch guidewire and stent delivery system were then removed and the main-branch stent deployed. Following this, the side-branch was rewired and a final kissing-balloon inflation (FKI) was performed. Meticulous efforts, including use of multiple wires, were made to ensure successful FKI. Drug-eluting stents were used in all cases. Radial artery hemostasis was achieved with a TR band (Terumo Corporation).

Procedural outcome. Procedural outcomes included: successful crush stenting via a 7 Fr transradial approach; successful two-stent bifurcation treatment (any technique) via the transradial approach; or successful crush stenting (via femoral or radial access). In cases of crush stenting, successful FKI, procedural time, contrast use, and fluoroscopy time were recorded. Markers of myocyte necrosis were not routinely measured.

Quantitative coronary angiography. In patients undergoing crush stenting, quantitative coronary angiography (QCA) was performed in two orthogonal views following intracoronary injection of glyceryl trinitrate. The main-vessel proximal and distal reference diameters and the side-branch distal reference diameter were measured. Minimum lumen diameter was measured in the main vessel and side branch before and after the procedure.

Clinical outcome. Routine follow-up clinical evaluation at 6 months was performed, as is the usual practice at our center. The rate of death, myocardial infarction, or target vessel revascularization at this timepoint was recorded. Angiographic follow-up was not performed and most patients were discharged from routine follow-up at this point. In addition, 18-month outcomes were obtained by note review and long-term mortality data were obtained by interrogating the United Kingdom National Patient Database in April 2013.

Results

During the study period, a total of 348 bifurcation lesions were treated out of 1038 PCI procedures performed in our institution. One hundred ninety-two of these lesions had a side-branch diameter of ≥2.25 mm; of these, 55 lesions were scheduled to undergo transradial crush stenting. Two patients had two suitable bifurcation lesions, which were treated in a staged fashion. The remaining 137 lesions were all planned for a provisional T-stent strategy. Conversion to a two-stent strategy because of side-branch compromise was required in only 3 of these cases, which were all treated with T-stenting. Figure 1 shows a diagram of patient flow through the study. Patient baseline characteristics are shown in Table 1.

Feasibility of radial access. Radial access was obtained in all patients and was well tolerated, without occurrence of limiting radial spasm. Successful crush stenting via the radial artery was performed in 51/55 lesions (93%). In 2 patients, a small-caliber radial artery precluded the use of a 7 Fr sheath; these cases occurred early in the series before the availability of sheathless guides. Bifurcation stenting was still performed via the radial approach, but using a 6 Fr sheath and a culotte technique. Therefore, successful two-stent bifurcation treatment was performed transradially in 53/55 lesions (96%). In another 2 patients, the procedure was not able to be performed successfully via the radial approach. In 1 patient, there was poor guide catheter support and extreme angulation of the side branch. In the other patient, the right radial artery was occluded and, although left radial arterial access was obtained, a radial loop prevented guide catheter passage. In both of these patients, successful crush stenting was performed by a 7 Fr femoral artery approach.

Of the successful radial crush procedures, 7 Fr guides were used in 46 cases (90%) and 7.5 Fr sheathless guides (Eaucath; Asahi Intecc) in 5 cases (10%). 

Procedural success of crush stenting. Crush stenting was successfully performed in 53/55 lesions (96%), with 51 lesions treated via the radial approach and 2 lesions treated via the femoral approach. Procedural characteristics for these procedures are documented in Table 2 and procedural QCA is shown in Table 3. Drug-eluting stents were used in all procedures (92% Taxus Liberte; Boston Scientific Corporation).

Final kissing balloon was successful in 51 procedures (96%). Six patients required more than one guidewire in the side branch and in 2 patients a Venture Wire Control catheter (St Jude Medical) was required to aid side-branch rewiring. 

Clinical outcome of crush stenting. No in-hospital or procedural complications were detected and, in particular, there were no vascular complications or cases of hand ischemia. The major adverse cardiovascular event (MACE) rate at 6 months was 5.9% (3/51). There was 1 non-ST elevation myocardial infarction and angiography in this patient demonstrated severe bifurcation restenosis, which was treated with coronary artery bypass grafting (CABG). Two other patients underwent target lesion revascularization with repeat PCI. There were no deaths or stent thromboses. At 18 months, there were 2 additional cases of CABG performed for diffuse restenoses involving both stented branches, giving a MACE rate of 9.8% (5/51). At a mean follow-up of 6.5 years, the overall mortality rate was 5.9% (3/51).

Discussion

The primary finding of this study is that crush stenting, necessitating a 7 Fr guide, can be routinely performed via the transradial approach with a very high success rate. We also show that crush stenting of true bifurcation lesions with meticulous efforts to perform FKI is associated with good clinical outcomes at 18 months.

Feasibility of radial access via large-bore sheaths. Transradial access is associated with reduced access-site complications, early patient mobilization, and reduced hospital stay.¹¹ Clinical outcomes may also be improved in some patients. The RIVAL study,¹ the largest randomized trial comparing radial and femoral access, showed a large reduction in vascular complications with the radial approach, and suggested better outcomes in high-volume radial PCI centers and a reduction in mortality in STEMI patients.

Six Fr sheaths are used in the majority of cases in contemporary PCI practice, since the use of larger sheaths from the femoral approach is associated with increased bleeding complications; the benefit of radial access may be more marked in these patients.¹² However, guides larger than 6 Fr in diameter are often not routinely considered when performing transradial intervention because of the relatively small size of the radial artery compared to the femoral artery.

Transradial procedures are well tolerated when the internal radial artery diameter is greater than the sheath diameter. Saito and colleagues found that the radial artery diameter is greater than a 7 Fr sheath in 72% of men and 40% of women in a Japanese population.³ This suggests that 7 Fr sheaths will be well tolerated in most men and a significant proportion of women. However, it is likely that the use of 8 or 9 Fr guiding catheters via the transradial route would be possible in only a minority of patients.

In this study, complex PCI via the transradial approach using a guide with a 7 Fr internal lumen size was successfully performed in 93% of cases (51/55 procedures). Additionally, successful two-stent bifurcation intervention was performed via the transradial approach in 96% of cases. The success rate is in keeping with a recently published retrospective series of complex PCI performed via transradial access using 7 Fr sheaths.¹³

Most successful cases in this series (90%) were performed using standard 7 Fr guiding catheters. However, toward the end of the series, sheathless Eaucath guide catheters became available, which enable the use of techniques requiring a 7 Fr guide even in patients with smaller radial arteries. Sheathless guides possess an internal lumen diameter of a 7.5 Fr guiding catheter (0.081˝), but an external diameter smaller than a 6 Fr sheath.^5,6 A similar sheathless approach has also been described using a 5 Fr multipurpose catheter as a dilator within a 7 Fr guide with a high success rate.¹⁴ There were 2 cases of unsuccessful 7 Fr access, which occurred early in our series: these patients underwent transradial intervention via a 6 Fr sheath, but it is likely that the procedures could have been completed via a sheathless guide had this technology been available at the time.

Radial artery occlusion (RAO) is the main vascular complication following radial access. RAO is almost always asymptomatic — in the RIVAL study, symptomatic RAO needing ultrasound confirmation occurred in only 0.2% of patients, none of whom required surgery.¹ However, the occurrence of RAO prevents access if further coronary procedures are required and rules out the use of the artery as a conduit for CABG. There are some data to suggest that larger sheath sizes may be associated with a higher rate of RAO.¹⁵ We did not routinely assess the prevalence of RAO in this study, but it is reassuring that there were no cases of symptomatic occlusion at 6-month clinical follow-up.

Although this study specifically looked at the use of large-bore guides for the purpose of crush stenting, it can be assumed that other techniques that require >6 Fr sheath (eg, rotational atherectomy with large burrs) could also be performed routinely via transradial approach.

Crush stenting for bifurcation disease. Randomized studies have shown that a single-stent strategy for bifurcation lesions is appropriate in the majority of cases.^7,8 However, these studies often included patients without true bifurcation disease, and bifurcations with large-diameter side branches subtending a large myocardial territory or with severe side-branch disease extending distal to the bifurcation may be best treated with a two-stent strategy.

The importance of FKI following crush stenting is well appreciated and successful FKI leads to a significant decrease in the rate of acute and long-term adverse outcomes.^16,17 However, FKI may be technically demanding, since multiple layers of stent cover reentry to the side branch. Most randomized studies of bifurcation strategy have reported relatively low rates of FKI following crush stenting. For instance, FKI was only achieved in 72% of lesions treated with crush stenting in the BBC ONE study, and in 74% of lesions treated with a two-stent strategy in the Nordic Bifurcation Study.^7,8 This is likely to have adversely affected the reported outcomes following crush stenting in these studies.  

In the current study, crush stenting for true bifurcation lesions carried a high procedural success rate and good medium-term outcomes, which is likely related to the very high rate of FKI achieved. Meticulous attempts were made to recross the side branch and successful FKI was performed in 96% of cases (51/53 patients). In 6 cases, a second extra-support buddy guidewire was placed next to the initial wire to allow a low-profile balloon to pass into the side branch. One case required three side-branch wires (two Choice PT Extra-Support wires and one Mailman wire) before a 1.1 mm balloon could be passed. Final kissing balloon inflation was unsuccessful in 2 patients. In the first case, the extreme angle of the side branch worsened after stent implantation and made advance of the balloon impossible. In the second case, a 1.5 mm balloon would not cross the stent struts. This case was performed prior to the advent of 0.85 mm and 1.1 mm low-profile balloons (Schwager Medica), which were used in several subsequent cases.

Various modifications to the classic crush stenting technique exist, although these may increase the procedural complexity. Although classic crush stenting requires a minimum 7 Fr guide, stepwise balloon crush stenting can be performed via 6 French guide and this technique has been described via radial approach.¹⁸ A recently described modification of this technique is to “double kiss.” This involves rewiring the side branch after initial stent deployment and performing an additional kissing balloon inflation prior to main-vessel stent deployment. Dilatation of the side branch stent facilitates final rewiring of the side branch after main-vessel stent deployment since the guidewire only has to traverse one layer of stent struts rather than three layers with classic crush stenting. In the DKCRUSH-II study of this technique, FKI was successfully performed in all cases and crush stenting resulted in decreased angiographic restenosis at 8 months and a decrease in target lesion revascularization at 12 months as compared to the provisional stenting group.⁹ The same group has also recently reported excellent 5-year outcomes following double-kiss crush stenting for distal left main stem bifurcation disease.¹⁹

Study limitations. There are a number of limitations with this study. First, there was no control group and there is likely to have been selection of patients prior to entering the study. For instance, patients with weak or impalpable radial pulses may not have been planned for a procedure requiring large-bore radial access. Second, female patients were under-represented. Given that women generally have smaller-diameter radial arteries than men, success rates may be lower than reported here. Third, Taxus stents were used in the majority of procedures. Modern-generation DESs have been shown to result in improved clinical outcomes and typically possess thinner strut diameters and more open cell designs, which may facilitate side-branch access for FKI and thus improve outcomes further. Fourth, although medium-term follow-up was favorable, conclusions cannot be drawn on the long-term outcomes of crush stenting from this study. Finally, the rate of RAO may be increased with large-bore sheaths and radial artery patency rates were not assessed.

Conclusions

Complex PCI requiring large-bore catheters can be performed successfully in a high proportion of patients via the transradial approach. Since there is an increased risk of femoral vascular complications with large-bore sheaths, transradial access should therefore be considered for all patients undergoing complex PCI requiring 7 Fr guide catheters.

Crush stenting, with a very high rate of FKI, was associated in this series with excellent procedural and medium-term outcomes, consistent with other larger studies. Crush stenting with mandatory FKI should be considered an appropriate strategy for bifurcation lesions in which a two-stent strategy is considered necessary. 

References

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From the ¹St Vincent’s Hospital, Melbourne, Australia, ²Blackpool Victoria Hospital, United Kingdom, and ³Manchester Heart Centre, United Kingdom.

Disclosure: The authors have completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest. The authors report no conflicts of interest regarding the content herein.

Manuscript submitted January 30, 2013, provisional acceptance given March 5, 2013, final version accepted May 13, 2013.

Address for correspondence: Paul D. Williams, MA, BM, BCh, MD, St Vincent’s Hospital Cardiology, St Vincent’s Hospital, Fitzroy, Melbourne, VIC 3065, Australia. Email: dr.pdwilliams@gmail.com